/**
 * @license Copyright (c) 2003-2023, CKSource Holding sp. z o.o. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
 */
/**
 * The table iterator class. It allows to iterate over table cells. For each cell the iterator yields
 * {@link module:table/tablewalker~TableSlot} with proper table cell attributes.
 */
export default class TableWalker {
    /**
     * Creates an instance of the table walker.
     *
     * The table walker iterates internally by traversing the table from row index = 0 and column index = 0.
     * It walks row by row and column by column in order to output values defined in the constructor.
     * By default it will output only the locations that are occupied by a cell. To include also spanned rows and columns,
     * pass the `includeAllSlots` option to the constructor.
     *
     * The most important values of the iterator are column and row indexes of a cell.
     *
     * See {@link module:table/tablewalker~TableSlot} what values are returned by the table walker.
     *
     * To iterate over a given row:
     *
     * ```ts
     * const tableWalker = new TableWalker( table, { startRow: 1, endRow: 2 } );
     *
     * for ( const tableSlot of tableWalker ) {
     *   console.log( 'A cell at row', tableSlot.row, 'and column', tableSlot.column );
     * }
     * ```
     *
     * For instance the code above for the following table:
     *
     *  +----+----+----+----+----+----+
     *  | 00      | 02 | 03 | 04 | 05 |
     *  |         +----+----+----+----+
     *  |         | 12      | 14 | 15 |
     *  |         +----+----+----+    +
     *  |         | 22           |    |
     *  |----+----+----+----+----+    +
     *  | 30 | 31 | 32 | 33 | 34 |    |
     *  +----+----+----+----+----+----+
     *
     * will log in the console:
     *
     *  'A cell at row 1 and column 2'
     *  'A cell at row 1 and column 4'
     *  'A cell at row 1 and column 5'
     *  'A cell at row 2 and column 2'
     *
     * To also iterate over spanned cells:
     *
     * ```ts
     * const tableWalker = new TableWalker( table, { row: 1, includeAllSlots: true } );
     *
     * for ( const tableSlot of tableWalker ) {
     *   console.log( 'Slot at', tableSlot.row, 'x', tableSlot.column, ':', tableSlot.isAnchor ? 'is anchored' : 'is spanned' );
     * }
     * ```
     *
     * will log in the console for the table from the previous example:
     *
     *  'Cell at 1 x 0 : is spanned'
     *  'Cell at 1 x 1 : is spanned'
     *  'Cell at 1 x 2 : is anchored'
     *  'Cell at 1 x 3 : is spanned'
     *  'Cell at 1 x 4 : is anchored'
     *  'Cell at 1 x 5 : is anchored'
     *
     * **Note**: Option `row` is a shortcut that sets both `startRow` and `endRow` to the same row.
     * (Use either `row` or `startRow` and `endRow` but never together). Similarly the `column` option sets both `startColumn`
     * and `endColumn` to the same column (Use either `column` or `startColumn` and `endColumn` but never together).
     *
     * @param table A table over which the walker iterates.
     * @param options An object with configuration.
     * @param options.row A row index for which this iterator will output cells. Can't be used together with `startRow` and `endRow`.
     * @param options.startRow A row index from which this iterator should start. Can't be used together with `row`. Default value is 0.
     * @param options.endRow A row index at which this iterator should end. Can't be used together with `row`.
     * @param options.column A column index for which this iterator will output cells.
     * Can't be used together with `startColumn` and `endColumn`.
     * @param options.startColumn A column index from which this iterator should start.
     * Can't be used together with `column`. Default value is 0.
     * @param options.endColumn A column index at which this iterator should end. Can't be used together with `column`.
     * @param options.includeAllSlots Also return values for spanned cells. Default value is "false".
     */
    constructor(table, options = {}) {
        /**
         * Indicates whether the iterator jumped to (or close to) the start row, ignoring rows that don't need to be traversed.
         */
        this._jumpedToStartRow = false;
        this._table = table;
        this._startRow = options.row !== undefined ? options.row : options.startRow || 0;
        this._endRow = options.row !== undefined ? options.row : options.endRow;
        this._startColumn = options.column !== undefined ? options.column : options.startColumn || 0;
        this._endColumn = options.column !== undefined ? options.column : options.endColumn;
        this._includeAllSlots = !!options.includeAllSlots;
        this._skipRows = new Set();
        this._row = 0;
        this._rowIndex = 0;
        this._column = 0;
        this._cellIndex = 0;
        this._spannedCells = new Map();
        this._nextCellAtColumn = -1;
    }
    /**
     * Iterable interface.
     */
    [Symbol.iterator]() {
        return this;
    }
    /**
     * Gets the next table walker's value.
     *
     * @returns The next table walker's value.
     */
    next() {
        if (this._canJumpToStartRow()) {
            this._jumpToNonSpannedRowClosestToStartRow();
        }
        const row = this._table.getChild(this._rowIndex);
        // Iterator is done when there's no row (table ended) or the row is after `endRow` limit.
        if (!row || this._isOverEndRow()) {
            return { done: true, value: undefined };
        }
        // We step over current element when it is not a tableRow instance.
        if (!row.is('element', 'tableRow')) {
            this._rowIndex++;
            return this.next();
        }
        if (this._isOverEndColumn()) {
            return this._advanceToNextRow();
        }
        let outValue = null;
        const spanData = this._getSpanned();
        if (spanData) {
            if (this._includeAllSlots && !this._shouldSkipSlot()) {
                outValue = this._formatOutValue(spanData.cell, spanData.row, spanData.column);
            }
        }
        else {
            const cell = row.getChild(this._cellIndex);
            if (!cell) {
                // If there are no more cells left in row advance to the next row.
                return this._advanceToNextRow();
            }
            const colspan = parseInt(cell.getAttribute('colspan') || '1');
            const rowspan = parseInt(cell.getAttribute('rowspan') || '1');
            // Record this cell spans if it's not 1x1 cell.
            if (colspan > 1 || rowspan > 1) {
                this._recordSpans(cell, rowspan, colspan);
            }
            if (!this._shouldSkipSlot()) {
                outValue = this._formatOutValue(cell);
            }
            this._nextCellAtColumn = this._column + colspan;
        }
        // Advance to the next column before returning value.
        this._column++;
        if (this._column == this._nextCellAtColumn) {
            this._cellIndex++;
        }
        // The current value will be returned only if current row and column are not skipped.
        return outValue || this.next();
    }
    /**
     * Marks a row to skip in the next iteration. It will also skip cells from the current row if there are any cells from the current row
     * to output.
     *
     * @param row The row index to skip.
     */
    skipRow(row) {
        this._skipRows.add(row);
    }
    /**
     * Advances internal cursor to the next row.
     */
    _advanceToNextRow() {
        this._row++;
        this._rowIndex++;
        this._column = 0;
        this._cellIndex = 0;
        this._nextCellAtColumn = -1;
        return this.next();
    }
    /**
     * Checks if the current row is over {@link #_endRow}.
     */
    _isOverEndRow() {
        // If #_endRow is defined skip all rows after it.
        return this._endRow !== undefined && this._row > this._endRow;
    }
    /**
     * Checks if the current cell is over {@link #_endColumn}
     */
    _isOverEndColumn() {
        // If #_endColumn is defined skip all cells after it.
        return this._endColumn !== undefined && this._column > this._endColumn;
    }
    /**
     * A common method for formatting the iterator's output value.
     *
     * @param cell The table cell to output.
     * @param anchorRow The row index of a cell anchor slot.
     * @param anchorColumn The column index of a cell anchor slot.
     */
    _formatOutValue(cell, anchorRow = this._row, anchorColumn = this._column) {
        return {
            done: false,
            value: new TableSlot(this, cell, anchorRow, anchorColumn)
        };
    }
    /**
     * Checks if the current slot should be skipped.
     */
    _shouldSkipSlot() {
        const rowIsMarkedAsSkipped = this._skipRows.has(this._row);
        const rowIsBeforeStartRow = this._row < this._startRow;
        const columnIsBeforeStartColumn = this._column < this._startColumn;
        const columnIsAfterEndColumn = this._endColumn !== undefined && this._column > this._endColumn;
        return rowIsMarkedAsSkipped || rowIsBeforeStartRow || columnIsBeforeStartColumn || columnIsAfterEndColumn;
    }
    /**
     * Returns the cell element that is spanned over the current cell location.
     */
    _getSpanned() {
        const rowMap = this._spannedCells.get(this._row);
        // No spans for given row.
        if (!rowMap) {
            return null;
        }
        // If spans for given rows has entry for column it means that this location if spanned by other cell.
        return rowMap.get(this._column) || null;
    }
    /**
     * Updates spanned cells map relative to the current cell location and its span dimensions.
     *
     * @param cell A cell that is spanned.
     * @param rowspan Cell height.
     * @param colspan Cell width.
     */
    _recordSpans(cell, rowspan, colspan) {
        const data = {
            cell,
            row: this._row,
            column: this._column
        };
        for (let rowToUpdate = this._row; rowToUpdate < this._row + rowspan; rowToUpdate++) {
            for (let columnToUpdate = this._column; columnToUpdate < this._column + colspan; columnToUpdate++) {
                if (rowToUpdate != this._row || columnToUpdate != this._column) {
                    this._markSpannedCell(rowToUpdate, columnToUpdate, data);
                }
            }
        }
    }
    /**
     * Marks the cell location as spanned by another cell.
     *
     * @param row The row index of the cell location.
     * @param column The column index of the cell location.
     * @param data A spanned cell details (cell element, anchor row and column).
     */
    _markSpannedCell(row, column, data) {
        if (!this._spannedCells.has(row)) {
            this._spannedCells.set(row, new Map());
        }
        const rowSpans = this._spannedCells.get(row);
        rowSpans.set(column, data);
    }
    /**
     * Checks if part of the table can be skipped.
     */
    _canJumpToStartRow() {
        return !!this._startRow &&
            this._startRow > 0 &&
            !this._jumpedToStartRow;
    }
    /**
     * Sets the current row to `this._startRow` or the first row before it that has the number of cells
     * equal to the number of columns in the table.
     *
     * Example:
     * 	+----+----+----+
     *  | 00 | 01 | 02 |
     *  |----+----+----+
     *  | 10      | 12 |
     *  |         +----+
     *  |         | 22 |
     *  |         +----+
     *  |         | 32 | <--- Start row
     *  +----+----+----+
     *  | 40 | 41 | 42 |
     *  +----+----+----+
     *
     * If the 4th row is a `this._startRow`, this method will:
     * 1.) Count the number of columns this table has based on the first row (3 columns in this case).
     * 2.) Check if the 4th row contains 3 cells. It doesn't, so go to the row before it.
     * 3.) Check if the 3rd row contains 3 cells. It doesn't, so go to the row before it.
     * 4.) Check if the 2nd row contains 3 cells. It does, so set the current row to that row.
     *
     * Setting the current row this way is necessary to let the `next()`  method loop over the cells
     * spanning multiple rows or columns and update the `this._spannedCells` property.
     */
    _jumpToNonSpannedRowClosestToStartRow() {
        const firstRowLength = this._getRowLength(0);
        for (let i = this._startRow; !this._jumpedToStartRow; i--) {
            if (firstRowLength === this._getRowLength(i)) {
                this._row = i;
                this._rowIndex = i;
                this._jumpedToStartRow = true;
            }
        }
    }
    /**
     * Returns a number of columns in a row taking `colspan` into consideration.
     */
    _getRowLength(rowIndex) {
        const row = this._table.getChild(rowIndex);
        return [...row.getChildren()].reduce((cols, row) => {
            return cols + parseInt(row.getAttribute('colspan') || '1');
        }, 0);
    }
}
/**
 * An object returned by {@link module:table/tablewalker~TableWalker} when traversing table cells.
 */
class TableSlot {
    /**
     * Creates an instance of the table walker value.
     *
     * @param tableWalker The table walker instance.
     * @param cell The current table cell.
     * @param anchorRow The row index of a cell anchor slot.
     * @param anchorColumn The column index of a cell anchor slot.
     */
    constructor(tableWalker, cell, anchorRow, anchorColumn) {
        this.cell = cell;
        this.row = tableWalker._row;
        this.column = tableWalker._column;
        this.cellAnchorRow = anchorRow;
        this.cellAnchorColumn = anchorColumn;
        this._cellIndex = tableWalker._cellIndex;
        this._rowIndex = tableWalker._rowIndex;
        this._table = tableWalker._table;
    }
    // @if CK_DEBUG // public get isSpanned(): unknown { return throwMissingGetterError( 'isSpanned' ); }
    // @if CK_DEBUG // public get colspan(): unknown { return throwMissingGetterError( 'colspan' ); }
    // @if CK_DEBUG // public get rowspan(): unknown { return throwMissingGetterError( 'rowspan' ); }
    // @if CK_DEBUG // public get cellIndex(): unknown { return throwMissingGetterError( 'cellIndex' ); }
    /**
     * Whether the cell is anchored in the current slot.
     */
    get isAnchor() {
        return this.row === this.cellAnchorRow && this.column === this.cellAnchorColumn;
    }
    /**
     * The width of a cell defined by a `colspan` attribute. If the model attribute is not present, it is set to `1`.
     */
    get cellWidth() {
        return parseInt(this.cell.getAttribute('colspan') || '1');
    }
    /**
     * The height of a cell defined by a `rowspan` attribute. If the model attribute is not present, it is set to `1`.
     */
    get cellHeight() {
        return parseInt(this.cell.getAttribute('rowspan') || '1');
    }
    /**
     * The index of the current row element in the table.
     */
    get rowIndex() {
        return this._rowIndex;
    }
    /**
     * Returns the {@link module:engine/model/position~Position} before the table slot.
     */
    getPositionBefore() {
        const model = this._table.root.document.model;
        return model.createPositionAt(this._table.getChild(this.row), this._cellIndex);
    }
}
/**
 * This `TableSlot`'s getter (property) was removed in CKEditor 5 v20.0.0.
 *
 * Check out the new `TableWalker`'s API in the documentation.
 *
 * @error tableslot-getter-removed
 * @param getterName
 */
// @if CK_DEBUG // function throwMissingGetterError( getterName: string ): void {
// @if CK_DEBUG //		throw new CKEditorError( 'tableslot-getter-removed', null, {
// @if CK_DEBUG //			getterName
// @if CK_DEBUG //		} );
// @if CK_DEBUG // }
